Chapter 23 WAN Optimization, Web Cache, Explicit Proxy, and WCCP : Example network topologies : WCCP topologies
  
WCCP topologies
You can operate a FortiGate unit as a Web Cache Communication Protocol (WCCP) router or cache engine. As a router, the FortiGate unit intercepts web browsing requests from client web browsers and forwards them to a WCCP cache engine. The cache engine returns the required cached content to the client web browser. If the cache server does not have the required content it accesses the content, caches it and returns the content to the client web browser.
Figure 325: WCCP topology
FortiGate units can also operate as WCCP cache servers, communicating with WCCP routers, caching web content and providing it to client web browsers as required.
WCCP is transparent to client web browsers. The web browsers do not have to be configured to use a web proxy.